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Optical disc apparatus and optical disc replay methodOptical disc apparatus and optical disc replay method description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20090262633, Optical disc apparatus and optical disc replay method. Brief Patent Description - Full Patent Description - Patent Application Claims
The present invention contains subject matter related to Japanese Patent Application JP 2008-108228 filed in the Japanese Patent Office on Apr. 17, 2008, the entire contents of which being incorporated herein by reference. 1. Field of the Invention The present invention relates to an optical disc apparatus and an optical disc replay method that can suitably be used, for instance, for an optical disc apparatus for reproducing information from an optical disc where information is recorded. 2. Description of the Related Art Optical disc apparatus for emitting a light beam onto an optical disc such as a compact disc (CD), a digital versatile disc (DVD) or a Blu-ray disc (registered trademark: to be referred to as BD hereinafter) and reproducing information from the disc by reading reflected light have become very popular. With regard to optical discs, it is known that the size of the light spot formed on the optical disc is defined to be about λ/NA (λ: light beam wavelength, NA: numerical aperture) and the resolution is proportional to this value. With the BD system, for example, about 25 GB of data can be recorded on an optical disc with a diameter of 120 mm. Optical discs are being used to record various pieces of information such as audio contents, video contents and a variety of computer data. The quantity of information to be recorded on an optical disc has increased because of the availability of high definition images and high quality sounds, so that there is a demand for large capacity optical discs that can record a large number of contents. Optical disc apparatus designed to form a plurality of layers of recording marks in the uniform recording layer of an optical disc in a recording operation have been proposed in order to realize large capacity optical discs (refer to, e.g., Jpn. Pat. Appln. Laid-Open Publication No. 2007-220206 [FIGS. 1, 4 and 5]). Such an optical disc apparatus converges a light beam so as to focus the light beam onto a recording mark that may be formed on an optical disc and receives reflected light that is produced as the light beam is reflected by the recording mark that may be there. Then, the optical disc apparatus recognizes the presence or absence of a recording mark there from received light and executes a predetermined demodulation process and a predetermined decoding process in order to ultimately reproduce information. When, for instance, such an optical disc apparatus reproduces information from an optical disc, it needs to highly accurately focus the light beam onto the recording mark. Particularly, when a plurality of recording mark layers are formed in the optical disc, the focus position of the light beam needs to be adjusted two-dimensionally. More specifically, the optical disc apparatus needs to control the position of the objective lens and so on highly accurately by means of a servo mechanism or the like. Thus, there arises a problem that it inevitably needs a complex objective lens control mechanism to consequently make itself sophisticated and large. The present invention has been made in view of the above-identified problem and proposes an optical pickup and an optical disc apparatus that can accurately reproduce information from an optical disc with a simple arrangement. In order to solve the problem, the present invention provides an arrangement for an emission step of: emitting a reproducing light beam not to be converged to a single spot at the time of convergence from a predetermined reproducing light source onto an optical disc having a recording layer including one or more mark layers bearing a plurality of recording marks representing respective pieces of information arranged on a virtual plane and a reflection surface for reflecting the light beam to be used for reproducing the information; changing the angle of divergence of the reproducing light beam into substantially collimated light from the irradiation surface side opposite to the reflection surface with the recording layer interposed between them in the optical disc by a predetermined objective lens and irradiating with collimated light so as to include the target position in the target mark layer; having a detection region being provided at the confocal point with the target position of the reproducing light beam passed through the recording layer, reflected by the reflection layer and passed through the recording layer and the objective lens once again to detect the quantity of light in the detection region; and recognizing the presence or absence of the recording mark at the target position on the basis of the outcome of detection in the detection region in order to reproduce the information. Thus, according to an aspect of the present invention, when a reproducing light beam of substantially collimated light is emitted so as to include a target position, it is possible to detect that the reproducing light beam is blocked by a recording mark on the basis of the outcome of detection in a detection region at the confocal point of the target position and recognize the presence or absence of the recording mark at the target position. According to the present invention, when a reproducing light beam of substantially collimated light is emitted so as to include a target position, it is possible to detect that the reproducing light beam is blocked by a recording mark according to the outcome of detection in a detection region at the confocal point of the target position and recognize the presence or absence of a recording mark at the target position so that it is now possible to realize an optical pickup and an optical disc apparatus having a simple configuration that can accurately reproduce information from an optical disc. The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by like reference numerals or characters. Continue reading about Optical disc apparatus and optical disc replay method... Full patent description for Optical disc apparatus and optical disc replay method Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Optical disc apparatus and optical disc replay method patent application. Patent Applications in related categories: 20090285079 - Objective lens, optical pickup device, and optical recording/reproducing apparatus - De denotes an effective aperture (mm) of the light source side surface. NA denotes a numerical aperture on an optical recording medium side, and d denotes a thickness (mm) on an optical axis, ... 20090285078 - Objective lens, optical pickup device, and optical recording/reproducing apparatus - f denotes a focal length (mm). d denotes a thickness (mm) on an optical axis, and R2 denotes a radius of curvature (mm) of an optical recording medium side surface near the optical axis, ... ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Optical disc apparatus and optical disc replay method or other areas of interest. ### Previous Patent Application: Optical control device, optical information recording/reproducing device, optical information recording medium and optical head control method Next Patent Application: Focus optical system and optical disc master exposure apparatus Industry Class: Dynamic information storage or retrieval ### FreshPatents.com Support Thank you for viewing the Optical disc apparatus and optical disc replay method patent info. IP-related news and info Results in 3.16024 seconds Other interesting Feshpatents.com categories: Daimler Chrysler , DirecTV , Exxonmobil Chemical Company , Goodyear , Intel , Kyocera Wireless , paws |
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